DELETE THIS is challenge #45. The goal is to defeat ???. This challenge is unlocked by unlocking Tainted Eden. During this challenge, all items are randomly generated by randomly combining effects from other items in the game. Item sprites and text are randomly generated as well, providing no information on what each item does.
In addition to gameplay changes, the theme of each area, its obstacles per area, and music are randomized. Some obstacle sprites are randomized even within a level and sometimes the music may be missing altogether. Occasionally, even the floor texture might glitch out, replacing it with a plain color.
Try to get an active item that has a low charge or does something beneficial. Be warned, as items are randomly generated, active items could also just damage the player.
Item prices in shops can vary significantly, from as low as a single cent to as high as 99 cents.
Trinkets, Pills, Cards and Runes are unaffected by the randomization that TMTRAINER forces on other types of items; finding good trinkets such as Curved Horn or Cancer, as well as saving powerful cards such as XIX - The Sun for bad situations, can help give advantages despite your lower-than-usual stats.
Due to the inherent random nature of items, direct stat ups are very rare. As such, Bombs and XIII - Death gain increased utility during this challenge, as their relatively high damage is unaffected by randomization.
Once you have a reliable strategy, stop taking items, as some of their effects (replicating Damocles or mass spawning enemies) can end the run.
Try to finish the challenge as fast as possible, as a game crash is always randomly likely to happen from picking up just one item.
Taking a Deal with the Devil should only be done when having strong life bar: You have no guarantee to get a good item, so you might lose heart containers for nothing. Waiting for an Angel Room to spawn instead is a safer strategy.
It is possible for the challenge to be completed early if an item happens to spawn the ending trophy.
Due to the random nature of generated items, it is possible to find an item that makes completing the challenge trivial. Such as an active item with no charges, and deals damage to the whole room which can be spammed to clear each room. Or an item that grants a black heart whenever damage is taken which makes Isaac functionally invincible and causing mass damage whenever touched.
Unlike all other challenges, DELETE THIS appears below the challenge list itself, as an additional nameless challenge not numbered on the list.
The blank space where the invisible challenge "is" still gets crossed out after the challenge is complete, however.
All glitched items will appear as the icon for Mega Blast in the pause menu and death screen, though will keep their original glitched appearance on the Extra HUD.
You do not need to pick up the item that spawns after the Mom fight: Isaac will always be transported to the Chest after touching the golden chest that spawns in the Cathedral even if it doesn't seem like he has The Polaroid on him. This does not necessarily apply to golden chests randomly generated by items effects.
This challenge does not have a name in the game's files at all, and is not merely hidden from the menu: it is defined by the number 45 as its ID and a zero-length character string for a name. For clarity, it is referred to by the name of the achievement that unlocks it.
The TMTRAINER randomization is a reference to an old randomizer mod that came out before Afterbirth+.
If there is an effect that applies to spawned consumables, it will happen to the completion trophy, possibly causing completion to become impossible that run.
Ending chests spawned by an item will end the run but not necessarily mark the challenge completed.
Sometimes there is no music at all at the beginning of a floor. Entring a room where the music changes such as Treasure Room or Boss Room, or exiting the game and then continuing it, will make the music back for the rest of the floor.